Patent GB-575688-A (GB)
Title: Flying trainer
IPC: F41G9/02
Filed: 1943-12-16
Abstract: 575,688. Ground trainers for aircraft pilots. GENERAL AIRCRAFT, Ltd., and HARVEY, W. W. Dec. 16, 1943, No. 21145. [Class 4] A ground trainer comprises a cockpit capable of pivotal movement about a transverse axis and in the fore-and-aft vertical plane, a control column and throttle control in the cockpit, a simulated landing surface viewable by the pupil with the aid of a vision unit, the apparent speed of movement, attitude and height of the cockpit with respect to the simulated landing surface being varied in accordance with the rates of change of flight path angle and airspeed as determined by operation of the control column and throttle. The apparatus is intended more particularly to simulate the conditions obtaining during a landing approach run with the engine off, and to that end embodies mechanism for solving the following simplified equations for rate of change # of flight path angle #, and rate of change V of airspeed V, viz. : and General arrangement. The apparatus illustrated in Fig. 1 comprises a cockpit A provided with a dummy control column 4, throttle control lever 5 and airspeed indicator 7, and is carried by supports 11, being pivotally mounted on trunnions 12 permitting pitching movement in the fore-and-aft plane. The landing surface is simulated by an endless belt B which is driven by a variable-speed gear L in accordance with the assumed airspeed, and is movable in a vertical plane by levers 151 according to assumed height variation. The pupil views the surface through a vision unit C, preferably of the stereoscopic binocular type. Cockpit control mechanism. Movement of the cockpit is initiated by the control column 4, which is spring loaded to simulate aerodynamic loading, and is connected by a control 29 of the kind known under the Registered Trade Mark " Teleflex " to a response jack D (Fig. 3). The extent of movement is determined by two further jacks E, F, arranged in tandem, the former or wing incidence (alpha) jack being moved in accordance with angle of incidence as determined by movement of the control column, and the latter or flight path (#) jack introducing a correction to the alpha jack corresponding to the flight path angle. The jack control mechanism includes connections 71, 73 to cam boxes G, H (Fig. 4), comprising mechanism for solving the flight equations. The first equation is solved by a " lift coefficient" cam 74, a lever 80 whose angular displacement is proportional to the assumed airspeed V, and an eccentric 93 giving a 1 correction proportional to V. Movement of the lever and eccentric are communicated to rods 87, 89, whose differential motion is transmitted by a teleflex control 96 to the # trolley 129, of an integrating mechanism I (Figs. 6 and 7). The second equation is solved by a " drag coefficient " cam 75, a lever 81 whose displacement is proportional to V<2>, and a " Sin # cam 98. Differential movement of rods 88, 90 is transmitted by a teleflex 105 to the V trolley 145 of the integrator, and by a second teleflex 103 to the dummy throttle control lever 5. The integrating mechanism which may be of the kind described in Specification 568,262, [Group XXIX], comprises a continuously rotating drum 127 frictionally engaging the wheels 132 of the time derivative (#, V) trolleys 129, 145. The angles of tilt of the wheels being governed by the teleflex transmitters are proportional to the time derivatives, and their axial movement along the integrator drum proportional to the flight path angle and airspeed respectively. Movement of the # trolley 129 is transmitted by a connection 70 to the valve control mechanism of the " flight path angle " jack F, to impart the necessary correction to the " incidence " jack E. Axial movement of the V trolley 145 is communicated by a member 117 to an "airspeed" jack K (Fig. 5), the displacement of which is transmitted by cable 24 to the control column spring loading mechanism, by teleflex 123 to the dummy airspeed indicator 7, and by teleflex 51 to members 48, 50, of the jack control mechanism (Fig. 3), to effect the necessary response lag between the jacks D and E. Endless belt control mechanism. The variable speed gear L controlling the rate of traverse of the belt B is of the friction disc type, the ratio being governed by the " airspeed " jack K through a teleflex connection 124 (Fig. 5). Vertical movement of the belt, simulating altitude variation, is governed by movement of the H integrator trolley 130, which is connected to the # trolley by a teleflex 134. A cable 137 transmits the displacement of the trolley 130 to the crank arms 151 carrying the belt. The apparatus may be adapted for dual control, and may be provided with acoustic devices for simulating engine and taxying noises, together with means for simulating impact with the ground. An over-riding control may also be fitted to enable airspeed to be increased to gain flying speed from stall conditions or to maintain height, or to provide for tail-up take off above a given ground speed.